Dithia-dioxo-hydrocarbons



2,794,050 nrrrnA-moXo-HYnnocAnnoNs Ralph B. Thompson, Hinsdale, Ill.,assignor to Universal Oil Products Company, Des Plaines, 111., acorporation of Delaware No Drawing. Application November 17, 1953,

*' Serial No. 392,738

9 Claims. (Cl. 260--586) This application is a cont-inuation-in-part ofmy copending application Serial No. 175,019, filed July 20, 1950, nowabandoned, and relates to novel compositions of matter.

The novel compositions of matter comprise certain dithia-diketones inwhich the keto and sulfur groups are in a specific relation to eachother.

.In a specific embodiment the present invention relates to 'a novelcomposition of matter comprising a 4,6-dithia- 1,9-diketone.

In a more specific embodiment the present invention relates to a novelcomposition of matter comprising 5,7-dithia-6,6-dimethyl-2,lo-diketoundecane.

The novel compositions of matter may be illustrated by the-followinggeneral formula:

wherein each of R1, &, R3, R4, R and R6 is separately and independentlyselected from the members of groups consisting of hydrogen, hydrocarbon,substituted hydrocarbon, heterocyclic and substituted heterocyclicgroups. The hydrocarbon group preferably is selected from alkyl,alkenyl, cycloalkyl, cycloalkalkyl, alkcycloalkyl, aryl, alkaryl andaralkyl. The substituted groups may contain such radicals as hydroxyl,amino, monoalkylamino, dialkylamino, etc.

In another form of the invention, R1 and R4 may comprise carbon atomsforming a polymethylene ring.

It will be noted from the general formula hereinbefore set-forth thatthe keto groups are attached to carbon atoms in'positions beta to thesulfur atoms and the sulfur atoms. are attached to the same carbon atom.This specific configuration is present in all of the novel compositionsof the present invention and is essential thereto. These compounds arethioacetals (mercaptals and mercaptols) and are distinguished fromthioethers (sulfides). The diacetals may be hydrolyzed with dilute acidsto yieldthe starting materials, whereas the thioethers are stable underthe same conditions.

The novel compositions of the present invention may be used asintermediates in various organic synthesis. Furthermore, these compoundsare useful as antioxidants in retarding dxidative deterioration oforganic com- 2 molecular proportions of the mercapto-carbonyl compoundcombine with one molecular proportion of the carbonyl compound to formdithia-1,9-diketone which also may be referred to as adithia-diketoalkane.

The carbonyl compounds used as starting materials for reaction withhydrogen sulfide according to the present process include both aldehydesand ketones which may be represented by the formula:

wherein R1, Ra, R3 and R4 each separately and independently represents amember of the group consisting of hydrogen, hydrocarbon and heterocyclicgroups. The hydrocarbon groups which are represented by R1, R2, Ra andR4 include .alkyl, alkenyl, cycloalkyl, cycloalkalkyl, alkcycloalkyl,aryl, alkaryl and aralkyl. The heterocyclic rings which are representedalso by R1 to R4 include a thiophene ring, a furan ring, a pyridinering, etc. In. general, alpha-beta-unsaturated ketones are preferred andparticularly those in which R4 represents a hydrocarbon group and eachof R1, R2 and R3 represents a hydrogen atom, or R1 and Ra representhydrogen atoms and R2 represents a hydrocarbon group, particularly analkyl group.

The reaction of hydrogen sulfide with an alpha-betaunsaturated ketone iseffected readily by contacting these reacting materials generally at atemperature of from about 0 to about C. and preferably in the presenceof a catalyst. Ketones containing at least one hydrogen atom combinedwith the carbon atom in beta position to the keto group react readilywith hydrogen sulfide in the presence of a basic catalyst such aspiperidine, sodium methylate, quaternary ammonium hydroxides, and otherbasic acting catalysts. In some cases, it is desirable to heat thereaction mixture at a temperature of from about 50 to about 100C. inorder to promote the reaction. In most cases it is necessary to use alarge excess of hydrogen sufide in order to avoid reaction of twomolecules of alpha-beta-unsaturated ketone with one molecule of hydrogensulfide.

The mercapto-carbonyl compounds and particularly mercapto-ketones, whileformed by reacting hydrogen sulfide with an alpha-beta-unsaturatedcarbonyl compound, are condensed withan aldehyde or a ketone ashereinabove set forth to form a dithia-1,9-diketone. This condensationof a mercapto ketone with another carbonyl compound which does notcontain sulfur, is carried out by contacting two molecular proportionsof the mercapto ketone with one molecular proportion of the othercarbonyl compound in the presence of an acid catalyst and at atemperature of from about 0 to about 100 C.

The resultant condensation product is then separated from anyunconverted starting material which may be present in the reactionmixture.

The following specific preparations are illustrative of the large numberof compounds which may be prepared and used within the scope of thepresent invention. It is understood that all of these compounds are notnecessarily of equivalent activity for all uses. These compounds areprepared in accordance with the general procedure hereinbefore setforth.

The following specific compounds comprise those in which R1, R2 and R3are hydrogen and R4, R5 and Rs are alkyl groups.5,7-dithia-6,6-dimethyl-2,IO-diketoundecane is prepared by the reactionof methyl vinyl ketone with hydrogen sulfide to form methylbeta-mercaptoethyl ketone, followed by condensation of two moleculesthereof with one molecule of acetone. 6,8-dithia-7,7-dimethyl-3,ll-diketotridecane is prepared by "the reaction ofethyl vinyl ketone with hydrogen sulfide Patented May 28, 1957,

to form ethyl beta-mercaptoethyl ketone which then is condensed withacetone. 7,9-dithia-8,8-dimethyl-4,12- diketopentadecane is prepared bythe reaction of propyl vinyl ketone with hydrogen sulfide to ,formpropyl betalarly, dithia-diketononadccane, dithia-diketoheneicosane,j

dithiadiketotricosane, dithia-diketopentacosane, etc, may be prepared byutilizing, as starting material, amyl vinyl ketone, hexyl vinyl ketone,heptyl vinyl ketone, octyl vinyl ketone, etc. 7

In the compounds of the preceding paragraph, acetone is the c rb y copound u i ized n the n l ond n o s I th fo low n c mpqundsrd fi renketones are utilized. Thus, 5,7-dithia-6unethyl-6-ethyl-2,10dilgetotoundecane is prepared bythereaction of methyl vinyl ketone withhydrogen sulfide and subsequent condensation thereof with methyl ethylketone. 5,7-dithia- 6,6-diethyl-2,lO diketoundecane is prepared by thecondensation of the methyl beta-mercaptoethyl ketone (prepared byreacting methyl vinyl ketone with hydrogen sulfide) with diethyl ketone.Similarly, 5,7-dithia-6- methyl-6-propyl-2,IO-diketoundecane is preparedby utilizing methyl propyl ketone in the final condensation, and5,7-dithia-6-ethyl-6-butyl-2,IO-diketoundecatre is prepared by utilizingethyl butyl ketone in the final condensation step- As illustrative ofcompounds in which R1, R2, R4, R and Rs are alkyl groups and R3 isvhydrogen, 5,7-dithia- 4,4,6,6,8,8-heXamethyl-2,IO-diketoundecane may beprepared by the reaction of mesityl oxide with hydrogen sulfide andcondensation of two molecules of intermediate product with one moleculeof acetone. Similarly, 5,7-dithia-4,6,6,8-tetramethyl-4,8-diethyl-2,10diketoundecane may be prepared by the reaction ofmethyl(methylethylvinyl) ketone with hydrogen sulfide, followed bycondensation with acetone. In place of acetone other ketones may be usedin the preparation of the novel compounds of the present invention.Thus, in the following compounds mesityl oxide is reacted with hydrogensulfide and the intermediate product may be reacted with methyl ethylketone, diethyl ketone, methyl propyl ketone or ethyl butyl ketone toyield, respectively, 5,7: dithia-4,4,6,8,8 pentamethyl-6-ethyl 2,10diketoundecane, 5,7-dithia-4,4,S,8-tetramethyl 6,6-diethyl 2,10diketoundecane, 5,7 dithia-4,4,6,8,8-pentamethyl-6-propyl-2,10-diketoundecane or 5,7-dithia-4,4,8,8-tetramethyl-6-ethyl-6-butyl-2,lO-diketoundecane.

The following compounds illustrate those in which R4. comprises analkenyl radical. Allyl vinyl ketone is reacted with hydrogen sulfide andtwo molecules of the resultant product is condensed with one molecule ofacetone to yield 7,9-dithia-8,8-dimethyl-4,12-diketopentadecadiene-l,14.When utilizing methallyl vinyl ketone as the initial reactant and finalcondensation with acetone, the product is7,9-dithia-3,8,8,l3-tetramethyl-4,IZ-diketopentadecadiene-1,l4.Similarly, when starting with crotyl vinyl ketone, the product will be8,10-dithia9,9- dimethyl-5,13-diketoheptadecadiene-2,l5. When allylvinyl ketone is reacted with hydrogen sulfide andthe intermediateproduct is condensed with ethyl butyl ketone, the final product will be7,9 -dithia-8-ethyl-8-butyl-4,l2- diketopentadecadiene-l,l4.

As representative of compounds in which R4 is a cycloalkyl radical,4,6-dithia-l,9-dicyclohexyl-5,S-dimethyl- 1,9-diketononane may beprepared by the reaction of cyclohexyl vinyl ketone with hydrogensulfide and condensation of two molecular proportions of theintermediate product with one molecular proportion of acetone.Similarly, 4,6-dithia-l,9-dicyclohexyl-5-methyl 5 butyl-1,9-diketononane is prepared by the condensation of cyclohexyl vinylketone with hydrogen sulfide and con- 8,10-dithia-9,9 dirnethyl-5,l3 -diketoheptadecane is densation of the intermediate product with methylbutyl ketone. A compound containing an alkcycloalkyl radical may beprepared by the reaction of ethylcyclohexyl vinyl ketone with hydrogensulfide and condensation of the intermediate product with acetone toyield 4,6-dithia-1,9- di- (ethylcyclohexyl) -5 ,5 -dimethyle 1,9-diketononane.

As illustrative of compounds containing aryl groups,4,6-dithia-1,9-diphenyl5,5-dimethyl 1,9 diketononane may be prepared bythe reaction of phenyl vinyl ketone. with hydrogen sulfide to formphenyl beta-mercaptoethyl ketone, followed by condensation of twomolecules thereof with one molecule of acetone. Similarly,4,6dithial,9-dinaphthyl-5,S-dimethyl-1,9-diketononane may be prepared bythe reaction of naphthyl vinyl ketone with hydrogen sulfide andsubsequent condensation with acetone. Illustrative compounds in which R1and R4 are phenyl radicals, 4,6dithia-l,3,7,9-tetraphenyl-1,9-diketononane may be prepared by thereaction oflbeuzalacetophenone with hydrogenysulfide and subsequentcondensation with acetone. Illustrative of compoundsinwhich'Ri is phenyland R4 is alkyl,5,7 dithia-4,8-diphenyl, 2,10-diketoundecane is preparedby the reaction of benz alacetone with hydrogen sulfide andcondensation. of the intermediate product with acetone. In4,6-dithia-1,3,fL9-tetraphenyl1 Q 3,5,5,7-tetramethyl-1,9-diketononane,R1, R and Re are alkyl groups and R2 and R4 are phenyl groups. Thiscompound is prepared by the reaction of dypnone with 1 hydrogen sulfide,followed by condensation oi the intermediate product with acetoneCompounds containing alkaryl groups are illustrated by4,6-dithia-1,9-ditoly1- 5,5-dimethyl-1,9-diketononane, which may beprepared by the reaction of tolylvinyl ketone with hydrogen sulfide andcondensation of the intermediate product with acetone. Similarly,4,6-dithia-1,9-diXylyl-5,5-dimethyl-1,9- diketononane is prepared by thereaction of xylyl vinyl ketone with hydrogen sulfide and subsequentcondensation with acetone.

As illustrative of compounds containing heretocyclic groups,4,6-dithia-3,7-diphenyl-1,9-difuryl 1,9-diketo: nonane may be preparedby the reaction of benzalacetofurane with hydrogen sulfide andsubsequent condensation of two molecular proportions of'the productwithone molecular proportion of acetone. As illustrative of,

compounds in which R1 and R4 comprise carbon atoms forming apolymethylene ring, dimeth yll bis-.(3-ketocyclohexylthio)-methane maybe prepared by. the reaction of cyClohe'xenone-Z with hydrogen sulfideand subsequent condensation with acetone. l V 7 While the ketonesgenerally are preferred asfreactants,

it is understood that'aldehydes may be used as the initial reactantand/or as the carbonyl compound in the final condensation. Thus,4,6-dithia-5,5 -dimethylnonane?1,9- dial may be prepared by the'reaction of acrolein with hydrogen sulfide and condensation of twomolecules of the product with one molecule of acetone. 4,6-dithia-3,5,5,7 tetramethylnonane-1,9-dial may be prepared by the reaction ofcrotonaldehyde with hydrogen sulfide and subsequent condensation oftheintermediate product with acetone. Similarly,4,6-dithia-3,7-diphenylnonane '1,9- dial may be prepared by the reactionof cinnamaldehyde with hydrogen sulfide and subsequent condensation withacetone. Other compounds may be prepared by starting with differentalpha-beta-unsaturated aldehydes .and by using different ketones oraldehydes in the final con densation step. l v Q l The followingcompounds illustrate those in.which an alpha-beta-unsaturated ketone isutilized as the starting reactant and an aldehyde is used in the final.condensation step of the process. Thus, 5,7-dithia 6-phenyl-2,IO-diketouridecane may be prepared by the reaction of methyl vinylketone with hydrogen sulfide and subsequent condensation of twomolecules of the intermediate prod uct with one molecule ofbenzaldehyde. Similarly, mesityl oxide may be reacted with hydrogensulfide and the intermediate product is condensed with n-butyraldehydeto yield 5,7-dithia-4,4,8,8-tetramethyl-6-propyl- 2,10-diketoundecane.The following compounds are representative of those utilizing analpha-beta-unsat urated aldehyde as the initial reactant and an aldehydein the final condensation step. Thus, 4,6-dithia--propyl-1,9-diketononane may be prepared by the reaction of acrolein withhydrogen sulfide and subsequent condensation of two molecularproportions of the intermediate product with one molecular proportion ofnbutyraldehyde. 4,6-dithia-3,5,7-triphenyl 1,9-triphenyl-1,9-diketononane may be prepared by the reaction of cinnamaldehyde withhydrogen sulfide, followed by condensation of the intermediate productwith benzalaldehyde.

The following examples are introduced to illustrate further the noveltyand utility of the present invention but not with the intention ofunduly limiting the same.

Example I 5,7-dithia-6,6-dimethyl-2,IO-diketoundecane was prepared bythe two-step process represented by the following equations:

CHaC-CH=CH2+H2S OHaCOCHzCHzSH Example II In order to show the inhibitorpotency of the dithiadiketoundecane prepared in accordance with ExampleI, small quantities of this compound were added to lard which had anormal stability period of 5 hours. Upon the addition of the inhibitor,the stability period of the lard was increased as follows:

'Wt. of Additive 0.0

0. 005 Normal stability period, hours 8 The stability period of the lardwas determined by the Swift test, which is described in detail in thearticle by A. E. King, H. L. Roschen, and W. H. Irwin, in the Oil andSoap, vol. X, No. 6, pages 106109 (1933), and modified as described inthe article by R. W. Reimenschneider, J. Turer and R. M. Spec, whichappeared in the Oil and Soap, pages 169, 171, September 1943. Ingeneral, the test comprises bubbling air through a sample of the larduntil rancidity is determined organoleptically and by peroxide value,the lard being limited to a peroxide number of 20.

Example 111 5,7-dithia-4,4,8,8-tetramethyl 6 propyl 2,10 diketoundecanewas prepared by reacting mesityl oxide with hydrogen sulfide andsubsequent condensation with nbutyraldehyde. The reaction of mesityloxide with hydrogen sulfide was effected by adding 40% sodium methylatein methanol to mesityl oxide and passing hydrogen sulfide into themixture, accompanied by rapid stirring. An execess of hydrogen sulfideis unnecessary in this instance, since the two groups on the B-carbonatom hinder formation of the thiadiketone. While the hydrogen sultidewas being added, additional sodium methylate was added. After thereaction had been completed, the reaction mixture was washed with dilutesulfuric acid and with water. The product was distilled in vacuum toyield 2-methyl-2-mercapto-4-pentanone.

7.2 gms. of n-butyraldehyde was added to 26.4 gms. ofZ-methyl-2-mercapto-4-pentanone. The mixture was cooled in an ice bathand then saturated with anhydrous hydrogen chloride. The reactionmixture was dissolved in ether, and the water formed during the reactionWas removed. The ether solution was washed with dilute sodiumbicarbonate until all of the acid was removed, and then was washed withwater and dried over sodium sulfate. The product had a refractive indexn 1.5055.

Example IV 4, 6-dithia-3,5 ,5 ,7-tetramethylnonane-1,9-dia1 is preparedby reacting crotonaldehyde with hydrogen sulfide, separating theresultant mercapto aldehyde, and reacting two molecular proportionsthereof with one molecular proportion of acetone.

1 claim as my invention:

1. A dithia-dioxo-hydrocarbon having the following general formula:

0 R3 R1 R5 R1 R: O Rr-iLiJ--S--S- -dl-ii-R4 1'1 1'1. 1'1. I'M a whereineach of R1, R2, R3, R4, R5 and Re is separately and independentlyselected from the group consisting of hydrogen and hydrocarbon radicals.

2. A 5,7-dithia-2,IO-diketoundecane which is free of non-hydrocarbonsubstituents.

3. 5,7-dithia-6,6-dimethyl-2,IO-diketoundecane.

4. 5,7 dithia-4,4,6,6,8,8-hexamethyl-2,IO-diketoundecane.

5. 5,7 dithia-4,4,8,8-tetrarnethyl-6-propy1-2,10-diketo undecane.

6. A 4,6-dithia-1,9-diketononane which is free of nonhydrocarbonsubstituents.

7. 4,6 dithia-1,9-dicyclohexyl-S,S-dimethyl-1,9-diketononane.

8. A 4,6-dithia-1,9-diphenyl-1,9-diketononane which is free ofnon-hydrocarbon substituents.

9. A dithia-diketone free of non-hydrocarbon substituents and having inits structure the following arrangement of carbon, sulfur and oxygenatoms:

References Cited in the file of this patent UNITED STATES PATENTS2,010,828 Rothrock Aug. 13, 1935 2,492,335 Chenicek et a1. Dec. 27, 19492,492,336 Thompson et a1 Dec. 27, 1949

1. A DITHIA-DIOXO-HYDROCARBON HAVING THE FOLLOWING GENERAL FORMULA: